1. Interpreting Motion Graphs

2. Position vs. time graphs The slope of the graph is equal to the velocity The slope of the graph is equal to the velocity If the d/t graph is a straight line (no curve) then the velocity is constant. If the d/t graph is a straight line (no curve) then the velocity is constant.

3. Position vs. time graphs A line with a positive slope indicates positive velocity and the object is moving away from the reference point A line with a positive slope indicates positive velocity and the object is moving away from the reference point A line with a negative slope indicates negative velocity and the object is moving towards the reference point. A line with a negative slope indicates negative velocity and the object is moving towards the reference point.

4. Position vs. time graphs If the line is horizontal (no slope) then the object is stationary (no velocity) If the line is horizontal (no slope) then the object is stationary (no velocity)

5. If the object is accelerating, the velocity is changing If the object is accelerating, the velocity is changing d/t graph will no longer be a straight line, but will have a changing slope, resulting in a curve. d/t graph will no longer be a straight line, but will have a changing slope, resulting in a curve. Position vs. time graphs

6. Concave “Up like a cup”…the acceleration is positive Concave “Up like a cup”…the acceleration is positive

7. Concave “Down like a frown”…the acceleration is negative Concave “Down like a frown”…the acceleration is negative Position vs. time graphs

8. BEWARE: velocity and acceleration can have different signs: when they do the object is slowing down! BEWARE: velocity and acceleration can have different signs: when they do the object is slowing down! Position vs. time graphs

9. The slope is equal to the acceleration. The slope is equal to the acceleration. Because we only consider constant acceleration, v/t graphs will always be straight lines. Because we only consider constant acceleration, v/t graphs will always be straight lines. Velocity vs. time graphs

10. Positive velocity indicates the object is moving away from the reference point Positive velocity indicates the object is moving away from the reference point

11. Negative velocity indicates the object is moving toward the reference point Negative velocity indicates the object is moving toward the reference point Velocity vs. time graphs

12. When the slope is zero: When the slope is zero: –horizontal line – velocity is constant –acceleration is zero

13. Velocity vs. time graphs When the slope of the graph is positive: When the slope of the graph is positive: –the acceleration is positive

14. Velocity vs. time graphs When the slope of the graph is negative: When the slope of the graph is negative: – the acceleration is negative

15. We cannot determine where an object’s position from a v/t graph, only its change in position. We cannot determine where an object’s position from a v/t graph, only its change in position. Velocity vs. time graphs